Right now, Origin's On the House deal lets you play Nox and the Battlefield 4 Second Assault expansion for free! All you need to do is have to the Origin account. You can create one here. If you have the account, claim your games at the On the House's page. Nox is an action/RPG hybrid from the 2000's. And to play Battlefield 4 Second Assault you need to own a copy of the original Battlefield 4 game. However, if you don't have one, you can use Origin's trial version of Battlefield 4. It can be found here.